The American Cancer Society estimates that annually there are more than 350,000 new cases of breast or colorectal cancers and almost 100,000 deaths related to these cancers. This is a substantial public health problem that remains the focus the National Surgical Adjuvant Breast and Bowel Project (NSABP). For more than 50 years, the NSABP has successfully conducted large-scale, randomized clinical trials in breast and colorectal cancer designed to improve the standard of care, quality of life and survival of persons who develop these diseases. Since 1984, when NSABP became a CCOP Research Base, the CCOP investigators have accounted for approximately 30,000 treatment trial patients and more than 33,100 participants have been enrolled in the BCPT and STAR breast cancer prevention trials. The timeliness and quality of data obtained through these programs have been exceptional and have contributed positively to overall NSABP data integrity and have substantially enhanced the base of scientific information regarding the treatment and prevention of cancer. In the proposed project period, funding will be used to sustain our efforts as a data and statistical center in support of the NSABP CCOP treatment, cancer control and prevention scientific agenda. In that capacity, we will continue to enhance the utilization of newer technologies for data collection, data management and the communication and training of clinical site collaborators with the goal of developing more efficient methodologies to design, conduct and analyze clinical trials, This research proposal requests funding to enable the continued functioning of the CCOP, MB-CCOP and Prevention components of the NSABP Biostatistical Center which provide: 1) data management support for the collection and processing of data from NSABP trials; 2) quality assurance programs which ensure that the collected data is of the highest integrity; 3) scientific collaboration in the development of the NSABP research agenda and logistical support for the conduct of the research; and 4) statistical leadership and support for the design, monitoring and analysis of trials and correlative studies. RELEVANCE (See instructions): Breast and Colorectal cancer is a substantial public health problem that is the focus of the National Surgical Adjuvant Breast and Bowel Project (NSABP). The focus of the NSABP is the conduct of large-scale, clinical trials designed to improve the standard of care, quality of life and survival of persons who develop these diseases as well as the conduct of breast and colorectal cancer prevention studies. Our current and planned studies are designed to improve the prevention and treatment of these diseases.